The ghastly fate of Mr Skripal and his daughter (and, of course, a British policeman) seems particularly close to home if one lives not many miles away from Salisbury.
There will no doubt continue to be much debate and discussion about various aspects of this case for a long time to come. But certain things are already clear.
Following the whole lamentable episode involving purported weapons of mass destruction in Iraq and the subsequent discovery of no such weapons despite extensive searches, very many people have understandably become suspicious of any attribution to a foreign power of responsibility for anything in a case where there is anything less than absolute proof.
But when one is trying to learn from history, there are two equal and opposite dangers. The first is to ignore the significance of a pattern observed in the past and hence to repeat the same mistake as made in the past. The second, however, is to be so concerned about repeating the mistakes of the past that one makes mistakes in the present.
In this particular case, there is obviously a great deal that is murky and will never be known with any certainty. But some things we do know. Mr Skripal had been a Russian intelligence officer and was living in the U.K. following an exchange of prisoners. It is therefore not in doubt that he is someone who has betrayed the Russian state. It is also beyond doubt that the nerve agent used in the attack is one that has been manufactured in Russia: this has been revealed by someone who worked on the manufacture and has not been denied by the Russians.
Under the circumstances, there do indeed - as the Prime Minister pointed out - appear to be only two plausible explanations: either the Russian state used the nerve gas or the Russian state lost control of some of its nerve gas stocks to some other freelance operator.
Given that the Russian state has been entirely unforthcoming about any suggestion that they have lost control of any of the stocks - and given that Mr Putin would have every reason to cooperate with the rest of the world by investigating any such possible loss of control if the Russian state wanted to persuade others that it had not been involved in the attack - one is driven very clearly to the conclusion that Mr Putin is perfectly happy to be regarded as the author of the attack. And if he is happy to be regarded as the author of the attack, had the means to carry out the attack, and had previously made some rather blood curdling remarks about the likely fate of those who betrayed the Russian state the circumstantial evidence for supposing that this was an authorised act of state becomes compelling.
In short, this is not a case of a 'dodgy dossier' but of a compelling logic.